Thursday, September 23, 2010

Where is All the Plastic?

For a prolonged time the oceans have been subjected to human wastes and pollutants. Some of these pollutants are plastic debris that accumulate on the ocean surface and are brought together by ocean currents. This debris has negative effects on the oceans ecosystems as it can cause harm to the organisms who ingest the plastic or who become injured by coming into contact with it. Studies have been conducted by Kara Lavender Law and associates to try to quantify the amount of plastic debris in the western North Atlantic region and the Caribbean (Houlton 2010). A report of their research was collaborated. The report is Plastic Accumulation in the North Atlantic Subtropical Gyre and was found at http://www.sciencemag.org/cgi/reprint/329/5996/1185.pdf. Later Sarah Houlton wrote an article called, Plastic Ocean, based on their findings. Her article is posted at http://rsc.org/chemistryworld/News/2010/August/19081003.asp.

Both of the article’s talk about the surprising results of data that has been collected in the last few years. Considering the research that has been done, it seems as though that despite an increase in plastic production, the levels of plastic in the ocean have not risen in the area’s Law and her team have studied. Why the plastic levels do not seem to be increasing is very hard to determine. This is because there has not been enough studies done on the ocean plastic levels to give accurate data. There are still many area’s of ocean that have not been examined and such areas could be accumulating the unaccounted for plastic. It is also unknown where or how much new plastic is entering into the oceans from land. This makes it very hard to hypothesize the amount of plastic that should be found.

This figure shows areas of high plastic concentration based on the data collected between 1986 and 2008.

In the article by Sarah Houlton, the main points are given accurately. The ones that are extracted from the primary source are all given in the same context and there were no major details that were left out. The points given in the article were all very strong facts from the primary. For instance, the theories for why there has not been an increase in plastic levels, the secondary article takes the three most convincing statements. These points are “some of the plastic is broken down into even smaller pieces that cannot be captured by the net, organisms grow on the debris and cause it to sink to the bottom, and that organisms have adapted to use the plastic as a food source” (Houlton and Law 2010). The secondary article left out the theories that were not as strong. It does not mention the theory that the ocean currents may have shifted slightly. This theory was disproved in the original article as there have not been any significant shifts in the currents to account for the rise in plastic that should be present.

Although Houlton’s article presented the main article’s facts with precision, there were still a few weak points. There are many facts and information given in the article that were not mentioned in the primary source. Despite this there is only the one reference given. Where the additional information came from is not mentioned. For example, the types of plastics that are found near the surface of the ocean were listed in the secondary article, but a few of the plastics were not included in the primary source. There were also many quotes given that did not come from the primary article but their source is not referenced.

In the conviction of the secondary source, it makes it seem as though the primary article does not stress the limitations of it’s data. At the end of the article there is a statement given by a peer of Law, Richard Thompson, who points out the weakness in the research. He mentions that although there has been no evidence that shows an increase in plastic in the area of ocean Law’s team studied this does not mean that there has not been plastic accumulating in other regions (Houlton 2010). In the primary report the limitations of the data are clearly stated. It is revealed how there is only a meager amount of known data on the amount of plastic in the ocean, where it originated and why the levels of plastic do not seem to be increasing.

Despite the limitations of the secondary source it is still a very well written article. It presents strong facts from the primary source and does not make any assumptions with the data. Everything that is stated has the facts to back it up. The article works very well with the primary report. It gives a satisfactory summary of the information presented in the main article.